21. Units and Dimentions [Please refer to the attachment for the problem]

22. You hear a sound with level 80.0 dB and you are located 10.0 m from the sound source. What is the power being emitted by the sound source?

23. There is a 1.2 m distance between a crest and an adjacent trough in a series of waves on the surface of a lake. In 30 s, 35 crest pass a buoy anchored in the lake. What is the speed of these waves?

24. A clarinet has a fundamental frequency of 147 Hz, and, when played, has one end closed.
a. How many harmonics appear below 1350 Hz?
b. If an open end tube has the same fundamental frequency, how many harmonics appear below 1350 Hz?

25. What is the effective length of a clarinet which has a fundamental frequency of 147 Hz. (closed-open tube)

This solution is comprised of detailed step-by-step calculations and analysis of the given problems and provides students with a clear perspective of the underlying concepts.

The records of Midwestern University show that in one semester, 38% of the students failed mathematics, 27% of the students failed physics, and 9% of the students failed mathematics and physics. A student is selected at random.
a.) If a student failed physics, what is the probability that he or she failed mathematics?
b.)

A 0.025kg bullet traveling at 305m/s strikes a 1.500 kg ballistics pendulum hanging from a 2.00 m long string and buries itself in the block. How many degrees backward will the block swing? Do not use the law of conservation of momentum.

4 different math books, 2 different Chemistry books, and 6 different physics books are arranged on a shelf. How many different arrangements are possible if:
a.)The books in each particular subject must stand together?
b.)Only the math books must stand together?

1. A 5.3 g bullet leaves the muzzle of a rifle with a speed of 336 m/s. What force (assumed constant) is exerted on the bullet while it is traveling down the 0.92 m long barrel of the rifle?
2. A shopper in a supermarket pushes a loaded cart with a horizontal force of 12 N. The cart has a mass of 29 kg.
(a) How far will i